DC Connection Bus Inductance for Ripple Current Suppression
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Solution Overview
Problem
In power conversion apparatuses with multiple parallel-connected circuits, ripple currents generated by pulse width modulation (PWM) switching are difficult to reduce, especially when impedance components are minimized, leading to significant influence on the apparatus and space constraints due to the need for additional components like reactors and resistors.
Innovation Solution
The power conversion apparatus incorporates DC bus conductors with a thin-plate laminated shape and strategically positioned DC connection buses with an inductance component to inhibit ripple currents between units, eliminating the need for additional inductance components like reactors, thereby reducing the apparatus size while maintaining effective ripple current suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If components such as reactors and resistors are provided to reduce the ripple current, then the ripple current is reduced, but the power conversion apparatus becomes large
Solution Approach 1:
The patent combines the DC connection bus function with the inductance component function into a single structure. The DC connection bus is designed with a specific shape (extending in a direction intersecting the DC bus conductors) that inherently provides the necessary inductance to suppress ripple current, eliminating the need for separate reactor components.
Solution Approach 2:
The DC connection bus serves multiple functions: it electrically connects the power conversion circuit to the DC bus conductors while simultaneously acting as an inductance component to suppress ripple current. This multi-functional design reduces the overall apparatus size by eliminating dedicated ripple current suppression components.
2Device complexity
If a power conversion circuit is unitized, then the circuit is compact and integrated, but it is difficult to ensure sufficient space for components such as reactors and resistors
Solution Approach 1:
The patent merges the DC connection bus with the inductance function, integrating what would traditionally be separate components (connection bus and reactor) into a single unified structure. This allows the power conversion circuit to remain compact and unitized while still providing sufficient ripple current suppression capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively prevents ripple current flow between power conversion units, ensuring efficient power conversion without the need for additional space-consuming components, maintaining apparatus performance and reducing size constraints.
Implementation Method 1
DC connection buses (3P, 3N) having an inductance component which inhibits a ripple current caused by switching
Data Source
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Figure 3~4
AI summary
A power conversion apparatus includes power conversion circuits (1) including switching elements (4), a DC conductor (2P, 2N) which is provided in each of the power conversion circuits (1) and supplies a DC power to each of the power conversion circuits (1), and a DC connection bus (3P, 3N) which is provided in each of the power conversion circuits (1), has a length having an inductance for inhibiting a ripple current flowing from another power conversion circuit (1) as a result of switching of the switching element (4), and connects another power conversion circuit (1) and the DC conductor (2P, 2N).